1. Field of the Invention
This invention relates to a liquid crystal display device which facilitates connection between a number of finely spaced lead electrodes thereof and an external circuit.
2. Description of the Prior Art
A structure as described below has been used in the past to connect a liquid crystal display device to an external circuit. FIG. 1 shows a terminal structure applicable to a liquid crystal display device 1 having an electrode terminal spacing of 1.5 mm or more, and projecting leads to be connected to electrode terminals are inserted into a socket or soldered to a printed circuit board in order to connect them to an external circuit. This structure permits a firm connecting between the leads and the external circuit, but if the spacing is narrower, the structure is not useful because adjacent terminals are likely to contact each other. In case of a liquid crystal display device having electrode terminal spacing of 1.0 mm or more, a structure may be used wherein, as shown in FIG. 2, a pad including conductive rubber members 3 and insulating rubber members 4 disposed alternately at the same intervals as the electrode terminal spacing is placed in such a manner that the conductive rubber members 3 of the pad are located between the electrode terminals of the liquid crystal display device and the leads formed on a circuit board (not shown), and the electrode terminals and the lead terminals are electrically connected by a mechanical force applied therebetween. In this structure, the spacing between adjacent conductive rubber members 3 cannot substantially be reduced. When the spacing between terminals is further narrowed, another structure may be used wherein a pad including an insulating rubber sheet 6 and thin metal wires 5 (e.g. gold-plated wires) embedded therein, as shown in FIG. 3, is placed in such a manner that the thin metal wires 5 are located between the electrode terminals of the liquid crystal display device and the lead terminals printed on a circuit board, and the electrode terminals and the lead terminals are electrically connected by a mechanical force applied therebetween. This structure may be used for a device having a terminal spacing of as narrow as 0.5 mm. However, when a liquid crystal display device has a great number of terminals and thus is of a relatively elongated shape, the above-mentioned structures using such pads as shown in FIGS. 2 and 3 involve difficulty in applying an even force to provide good electrical connection between the electrode terminals and lead terminals, and may cause mechanical damage to the liquid crystal display device if a greater force is applied to provide good electrical connection.